The goal of the proposed work is to gain a detailed understanding of the visual representations that guide natural behavior. At the most fundamental level, this is necessary because so little is known about how vision is used in normal circumstances: where fixation is directed, what initiates a change in gaze, what information is extracted, and how it is used in behavior. Understanding natural vision requires specifying the temporal organization of visual information acquisition and eye and hand movement control over periods of a few seconds. Our previous work reveals the highly active and selective nature of visual processes, and the integral role played by saccadic eye movements. We hypothesize that the information extracted from the image during a fixation is fragmentary, and driven by the immediate task demands. In different fixations on a given location, different information may be acquired, although the retinal stimulation is identical in each case. Our research goal is to characterize the nature and extent of this selectivity. In addition, the experiments lay the foundation for a rigorous understanding of how elementary visual and motor operations are composed into more complex ongoing behavior. The experiments break new ground by developing paradigms in real and virtual environments to study how vision is used in ordinary tasks. The fragmentary and transient nature of visual representations presents a problem for coordinating larger behaviors. Visual representations must be sufficiently extensive to preserve the continuity of visual experience and mediate coordinated movements. Thus the experiments focus on what information is extracted and retained across fixations, whether it is used to guide subsequent eye and hand movements, and how different kinds of information are composed to make up larger behavioral units. Because they deal with natural behavior, and because eye, head, and hand movements are very revealing about information use, these experiments have fairly direct relevance to understanding how different visual impairments affect performance in normal life. Understanding the information needs of everyday tasks is critical for the development of specialized rehabilitation procedures.